• Lumbar sympathectomy was performed on 100 of 400 patients who had occlusive vascular disease. The operation was bilateral in 14 and unilateral in 86 patients; it consisted in removing that portion of the sympathetic chain between the diaphragm and the common iliac vessels, and generally included the second, third, and fourth lumbar ganglions. The first requirement in the selection of patients was the presence of subjective and objective evidence of vascular disease: intermittent claudication, rest pain, dependent congestion of the feet, weakness or absence of peripheral arterial pulsations confirmed by oscillometry, and poor skin temperature responses to vasodilator tests. The largest group consisted of 42 patients with main artery occlusion (proved by oscillometry) but good collateral circulation (proved by data on skin temperature and vasodilator responses); in this group the response to sympathectomy was excellent. Thorough preoperative study, careful preparation for surgery, and proper after-care contributed to good results. In properly selected cases the operation ends the hidrosis, mitigates the intermittent claudication, brings about the healing of lesions caused by ischemia, and frequently obviates the need of an amputation.